Dissolvable projectiles

ABSTRACT

A dissolvable glass projectile for a firearm is molded from dissolvable glass for the ammunitions and firearms industry. The dissolvable glass projectile may be molded into different sizes or geometry based on firearm and user preference. A mixture of chemicals components are heated and melted and then poured into a mold and is allowed to cool to a solid that can be handled.

FIELD

This relates to a dissolvable projectile, molded from a dissolvableglass material, which may be molded into varying shapes and sizes foruse as ammunition with a firearm.

BACKGROUND

Dissolvable glasses made up of various compositions are used formultiple applications that include wood preservation, bone repair, anddownhole processing. For example, U.S. Pat. No. 8,430,174 (Holderman etal.) entitled “Anhydrous boron-based timed delay plugs” describes theuse of dissolvable glass plugs manufactured from anhydrous boron fordownhole applications in hydrocarbon-producing wells.

SUMMARY

According to an aspect, there is provided a dissolvable glass projectilemolded from dissolvable glass.

According to another aspect, there is provided a projectile attached toa shell or casing, and the projectile may be a dissolvable glass pelletfor use in shotgun shells, or a projectile for use in a rifled barrel.

According to another aspect, the dissolvable glass projectile maycontain a tranquilizing component.

According to another aspect, the dissolvable glass projectile maycontain a vaccination and serve as a vessel.

According to another aspect, the dissolvable glass projectile maycontain an implant as a component.

According to another aspect, the mixture may comprise equal measures byweight of boric acid and disodium octaborate tetrahydrate.

According to another aspect, the mixture may comprise one or morecompounds selected from a group consisting of: hydrated alkalineborates, hydrated nonalkaline borates, refined borate, mineral borate,sodium borate, sodium metaborate, disodium octaborate tetrahydrate,borax, boric acid, copper borate, lithium borate, potassium borate,silver borate, zinc borate, boron halide, colemanite, kernite,probertite, tincal, and ulexite.

According to another aspect, there is provide a method of forming adissolvable projectile for a firearm, the projectile being formed ofamorphous borate, the method comprising the steps of: providing a boronmixture comprising one or more hydrated boron compounds; melting theboron mixture by heating the boron mixture to a target temperature;applying heat to release water from the boron mixture to form a moldableanhydrous boron compound; molding the moldable anhydrous boron compoundin a mold, the mold being maintained at a mold temperature that is abovean ambient temperature; cooling the moldable anhydrous boron compound toform a solid by maintaining the mold at the mold temperature for atleast 1 minute and then cooling the moldable anhydrous boron compound tothe ambient temperature over a period of at least 4 hours; and attachingthe solid to a casing or shell containing a propellant.

The method may further comprise any one or more of the followingaspects: the step of adding an additive to the mixture to adjust adissolve rate of the solid; the method may further comprise the step ofadjusting the dissolvability by adding an additive selected from a groupI, group II, and group III metal on the periodic table; the method mayfurther comprise the step of adjusting the dissolvability by adding anadditive selected from a group consisting of copper, manganese,molybdenum, zinc, calcium, and silver; the boron mixture comprises oneor more compounds selected from a group consisting of: hydrated alkalineborates, hydrated nonalkaline borates, refined borate, mineral borate,sodium borate, sodium metaborate, disodium octaborate tetrahydrate,borax, boric acid, copper borate, lithium borate, potassium borate,silver borate, zinc borate, boron halide, colemanite, kernite,probertite, tincal, and ulexite. The method may further comprise thestep of selecting the amount of the hydrated boron compounds in theboron mixture to adjust a dissolve rate of the solid; the mixture may beheated to a temperature of between about 340° F. and about 1900° F.; themixture may be heated to a temperature of between about 1500° F. andabout 1700° F.; the mixture may be poured into a mold having atemperature of between about 300° F. and about 1200° F.; the mixture maybe poured into a mold having a temperature of between about 600° F. andabout 900° F.; there may be a step of selecting the amount of the one ormore hydrous compounds in the mixture to adjust a dissolve rate of thesolid; the mixture may comprise one or more additives having at leastone of corrosion resistant and antibacterial properties.

According to another aspect, the anhydrous boron compound may comprisebetween about 12-20 mol % Na₂O and between about 80-88 mol % B₂O₃, orabout 18 mol % Na₂O and about 82 mol % B₂O₃.

According to an aspect, there is provided a dissolvable borate part,comprising an anhydrous borate compound that is molded to form an objecthaving a Young's Modulus of at least 30 GPa, the anhydrous boratecompound comprising between about 75 and 90% mol of B₂O₃; and betweenabout 10 and 25% mol of one or more alkali oxide.

According to another aspect, the dissolvable borate part may compriseabout 82 mol % of B₂O₃ and about 18 mol % of the one or more alkali, andthe object has a Young's Modulus of at least 40 GPa.

According to another aspect, a majority of the one or more alkali maycomprise Na₂O.

According to another aspect, the anhydrous borate compound may besubstantially free of silicate.

According to another aspect, the amount of alkali compound may be suchthat the alkali oxide is between 10-25%.

According to another aspect, the anhydrous boron compound may comprisebetween about 12-20 mol % Na₂O and between about 80-88 mol % B₂O₃, orabout 18 mol % Na₂O and about 82 mol % B₂O₃.

According to another aspect, the shape and geometry of the dissolvableglass may be machined or milled into any form.

According to an aspect, there is provided a projectile for a firearmcomprising a body molded from dissolvable glass. The body molded fromdissolvable glass may be attached to a casing or shell containing apropellant. The projectile may be designed for use in a firearm with arifled barrel, or the projectile may comprise a plurality of shot in ashotgun casing. The boron mixture may comprise equal measures of boricacid and disodium octaborate tetrahydrate.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features will become more apparent from the followingdescription in which reference is made to the appended drawings, thedrawings are for the purpose of illustration only and are not intendedto be in any way limiting, wherein:

FIG. 1 depicts a mixing step in the process of making a dissolvableglass.

FIG. 2 depicts a molding step in the process of making ammunition ofdissolvable glass.

FIG. 3a-3c are examples of shapes that may be used as ammunition.

FIG. 4 is a side elevation view of a cartridge for a rifle or handgun.

FIG. 5 is a side elevation view in section of a shotgun cartridge.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

This relates to projectiles made from a dissolvable glass material. Theprojectile can be made in various shapes and geometries to accommodatevarious firearms. The shape, design, or geometry of the dissolvableglass bullet will be dependent on the type of firearm and ammunition.Dissolvable glass bullets are molded from dissolvable glass and can beproduced as pellets or as tapered shapes that are made to withstand theconditions of use in a firearm, such as the high heat, impact, and speedthat will be experienced during use. The varying bullet sizes and shapesof the ammunition are easy to accommodate with the dissolvable glass asthe dissolvable glass may be molded or finished to any shape orgeometry.

The design of the dissolvable glass bullet needs to ensure that thebullet will not fragment upon being fired by the firearm. The propellantgenerates a hot gas when ignited, which increase the pressure in thebullet chamber. This pressure pushes on the base of the dissolvableglass bullet and causes the acceleration of the bullet. A commonpropellant used is gunpowder. As the propellant burns, more volume iscreated for the gas and as the dissolvable glass bullet travels down thebarrel, the volume of gas continues to increase causing furtheracceleration of the projectile. The dissolvable glass bullet must beable to withstand this heat and pressure. As the bullet is fired from arifle, the bullet experiences a slight deformation and expansion insidethe barrel of the firearm that causes the bullet to engage the riflingof the bore and this introduces the rotation to the bullet that helpsstabilize its flight for range and accuracy purposes.

The composition of the dissolvable glass bullet will be a dissolvablematerial, and in particular, a properly prepared anhydrous boron glass.An example of a process for preparing a suitable material will now begiven. Referring to FIG. 1, the method to form the dissolvable bulletsbegins by assembling an appropriate mixture of components 12. Thesecomponents will generally be in powder form as this allows thecomponents to be easily measured and mixed together, although thecomponents may be provided in other convenient states.

In one example, the components of the mixture include refined or mineralsources of boron. This may include hydrated alkaline and nonalkaline,mineral or refined borates, such as sodium borate, disodium octaboratetetrahydrate (DOT), sodium metaborate, borax, boric acid, metallicborate compounds such as copper, lithium, potassium, silver, and zinc,and other boron halide materials. Mineral borates may also be used, suchas colemanite, kernite, probertite, tincal, ulexite, Neobor™ (availablefrom Borax), etc. In addition, multiple sources of boron may be mixedtogether in equal or disproportionate amounts.

Some examples of formulations for making the dissolvable glass materialinclude: two-part mixtures made up of boric acid and DOT with about20-800 wt % and 20-80 wt % of each component being present in themixture; 95 wt % boric acid and 5 wt % DOT; 2.9 wt % copper hydroxide,7.1 wt % boric acid, and 90 wt % DOT; and 10 wt % copper hydroxide, 10wt % boric acid, and 80 wt % DOT. In another example, one or moresources of boron are mixed with one or more sources of alkali metal,such as Na, K, Li, or Ca, preferably one of which is in a hydrous form.For example, DoT is a hydrous form of Na, although Na may also be addedin other forms, such as NaOH, or a mixture of hydrous and non-hydrousforms. In addition, boron may be added in hydrous or non-hydrous forms,or combinations thereof. In order to increase modulus and strength ofthe glass, the Na content of the mixture must be increased. However, amixed alkali composition could also be used, such as by adding someadditional Li, or K, or Ca. These act as surface modifiers and rearrangethe crystalline structure of the glass molecules.

The mixture preferably has at least one hydrous compound, such that themixture is a hydrous mixture when melted. It has been found that thisassists in forming a moldable mixture once heated. Other mixtures mayalso be used. In one preferred example, the mixture was a two-partmixture made up of boric acid and DOT, with at least 25% and up to 75%of each component being present in the mixture. In another example, themixture may be composed of 95% boric acid and 5% DOT (disodiumoctaborate tetrahydrate). In a further example, the mixture may becomposed of 2.9% copper hydroxide, 7.1% boric acid, and 90% DOT. In anadditional further example, the mixture may be composed of 10% copperhydroxide, 10% boric acid, and 80% DOT.

The mixture of all components is mixed and melted to form a liquid stateuntil mixture 12 is at an appropriate state to be molded. While themixture is initially hydrous, sufficient heat is applied to remove thewater in the mixture such that the mixture is anhydrous once it ismolded in mold. Once heated properly to form a moldable mixture, themixture can be placed in mold 16 pertaining to the shape or geometry ofthe bullet type desired. The mixture must be heated properly and mustalso be allowed to anneal and cool properly in the mold. The mixture isfilled into the molds and allowed to cool until such time that themixture is solid and can be handled. The time after which the mixturecan be removed from the mold will vary by the size, shape, and mass ofthe bullet being molded. Once sufficiently cooled, the now solidifiedpart may be removed from the mold to continue conditioning to form astable solid.

In one example, equal portions of boric acid and DOT may be mixed andheated to about 1500° F. Generally speaking, the mixture may be heatedto between 340° F. and 1900° F. and more preferably between 1500° F. and1700° F. Once heated properly to form a moldable mixture, mixture canthen be placed in a mold, via pouring. The details of filling molds withmixture are known in the art and will not be described in more detailhere.

If the mixture is not heated properly, the resulting object may beweakened and may affect the consistency of the dissolvingcharacteristics of the part. It is believed that the weakness may resultfrom water present in the mixture, and that the effect can be reduced byproperly heating the mixture such that the mixture is molded in ananhydrous state. Care must be taken not to heat mixture too long, as themixture may set such that it cannot be poured. Also, it has been foundthat a solid anhydrous compound cannot be easily melted and re-moldedwithout a significant increase in the expenditure of energy required.

In one example, referring to FIG. 2, the melted mixture 12 may be pouredat a minimum temperature of 1500° F. into mold 16 that has been heatedto about 700° F. The mold may be at a temperature of between 400° F. and1500° F. Preferably, mold 16 temperature is between 600° F.-900° F. Ifthe mold temperature is below the minimum, it has been found that theresulting part is not sufficiently sound for the intended purpose. Ifthe mold temperature is too hot, it has been found that the mixtureadheres to the metal of the mold.

Once mold 16 is filled with the heated mixture 12, they are cooled untilthe mixture is a solid and can be handled. The time after which mixture12 can be removed from the mold will vary by the size and mass of objectbeing molded. It will be understood by one skilled in the art thatobjects of various diameters and shapes may be formed, and the coolingtime will increase as the size of the piece is increased. Care must betaken during these steps as a failure to condition the mixture properlymay result in cracking, splitting, deformation or failure of the objectprior to end use. Once sufficiently cooled, the now solidified part maythen be removed from the mold to continue conditioning to form a stablesolid.

Various different shapes of bullets and projectiles may be formed.Referring to FIG. 3a-3c , these may include semi oval shaped 20 as shownin FIG. 3a that may be used to form a cartridge 22 as shown in FIG. 4,tapered cone bullets 26 as shown in FIG. 3b , pellets 28 as shown inFIG. 3b that may be used for shotgun shells 30 as shown in FIG. 5, orothers, depending on the preferences of the user.

These glass bullets are designed to be dissolvable, although the rate atwhich the parts dissolve will depend on temperature, pressure, and thefluids encountered in the environment in which the dissolvable bullet issurrounded with. It is possible to adjust the dissolve rate of the partto be either longer or shorter, depending on the preferences of the userand the type of firearm. The dissolve rate may be modified based on theselection of the components used to create the mixture and the relativeproportions of the components in the mixture. The dissolve rate may alsobe adjusted through the use of additives, such as group I, group II, orgroup III metals on the periodic table. The dissolvable glass shape orgeometry may be used as a delivery method for compounds that act ascorrosion inhibitors, such as for example, copper, zinc, and silver.Additionally, the additives may deliver antibacterial compounds such assilver, copper, and zinc compounds or any metalloid that exhibitsantibacterial properties. Additives with other properties may also beincluded in the parts. In addition, other components may be added, suchas implants that may be embedded during the molding step. As examples,this may include a vaccination or tranquilizing agent for non-lethalusage of the bullet.

In this patent document, the word “comprising” is used in itsnon-limiting sense to mean that items following the word are included,but items not specifically mentioned are not excluded. A reference to anelement by the indefinite article “a” does not exclude the possibilitythat more than one of the element is present, unless the context clearlyrequires that there be one and only one of the elements.

The scope of the following claims should not be limited by the preferredembodiments set forth in the examples above and in the drawings, butshould be given the broadest interpretation consistent with thedescription as a whole.

1. A projectile for a firearm comprising: a body molded from dissolvableglass attached to a casing or shell containing a propellant.
 2. Theprojectile of claim 1, wherein the projectile is designed for use in afirearm with a rifled barrel.
 3. The projectile of claim 1, wherein thecasing or shell is a shotgun casing, and the body comprises a pluralityof shot in the shotgun casing.
 4. The projectile of claim 1, wherein thedissolvable glass is made from a boron mixture comprising equal measuresof boric acid and disodium octaborate tetrahydrate. 5-31. (canceled)